Conductive filament.



H. LYON. IOONDUG'IIVE FILAMENT. APPLIOATION FILED 00T. a, 1910.

Patented May 14, 1912.

iUNITED STATES PATENT OFFICE..

HOWARD LYON, 0F GLOUCESTER CITY, NEW JERSEY, ASSIGNOR TO WELSBACH LIGHT COMPANY, A CORPORATION 0F NEW JERSEY.

CONDUCTIVE FILAMENT.

To alt 'whom it may concern n Be it known that I, HOWARD LYoN, a citizen of the United States, and a resident 4of Gloucester City, in the county of Camden and State of New Jersey, have invented cer- -'tain new and useful Improvements in Conductive Filaments, of which the following is a description.

My invention relates to conductive filiaments for use in electric igniters, incandescent lamps and analogous devices in which high temperatures produced in such devices.

The invention consists briefly in the use l of a core of an' infusible or highly refrac- Y tory material'such as tantalum, tungsten or 30 minute cross section. Such material when` .,otherchighlyrefractory metal, upon which "is a sheathlof a metal of the platinum grou aorzanfalloy containing such metal. Suc 'filainent particularly useful in an elec` "tricjigniter'to-be affixed to gas burners. In

such devices,'in order to secure a.A high resistance anda concentrated heat-ing effect with a source of current of low voltage such Warmedfby an electric current in presence ofanexplosivemixture of illuminating gas and air is acted upon catalytically and is A heated to an extremely hio'h temperature by the chemical action which takes place.

'This high temperature tends to melt and destroy the filament, so that it may give way, at the first ignition or after a very few:

ignitions unless carefully protected. by special means for reducing or minimizing such temperatures, as disclosed for examplel in my application filed June 11, 1910, Serial By the use of an infusible core of tantalum, tungsten, orv other highlyV refractory metal, the effect of high temperature upon the sheath of platinum or platinum alloy is practically nullied since the particles of the latter are held in position and supported by the core. The filament -is capable of withstanding a temperature `suficient to cause the platinum to fuse inasmuch as the capillary action of the core will hold the fused metal in position thereon. As soon as the temperature falls sufficiently the specificatioa of Leiters Patent. Application iled October 3, 1910. I Serial No. 584,987.

'2 in any desired manner.

Patented May 14, 1912.

platinum solidifies and the filament is then in its original condition.

In order that the invention may be more fully understood, reference is made to the accompanying drawing in Which- Figure 1 is a side view, partly in section, of a fragment of the improved lament greatly magnified; and Figs. 2, 3 and 4 lare side views, partly in section, of various types of gas burner equipped with electric igniters employin the improved filament.

The filament 1 1s of minute cross section and is composed of an infusible or refractory core 2 of tantalum, tungsten, or other highly refractory metal. Upon the core 2 is a sheath 3 of platinum or a metal of the platinum group or an alloy containing platinum or such metal. Such metals and alloys when warmed or heated have a catalytic action upon illuminating gas. Any suitable mounting for supporting said filament and applying current thereto may be used, that shown comprising a metallic base 4 to whichfone end of the filament is joined and a conductor 5 carried by an insulator 6, the conductor being connected to the other `end of the filament.

The sheath 3 may be applied to the core For instance, when they core is of ductile material a sleeve of platinum or platinum alloy may be placed around the same and the Whole then drawn down to a small cross section. In case a non-ductile core is used a film of platinum or other metal may be deposited thereonin a partial vicuuii by a low, con-- Having now described' my invention, what I claim is: Y

1. A conductive filament `for igniters.V composed of a refractory metallic corefand a sheath consisting ofmaterial having a catalytic action upon illuminating gas.

taining a metal of the platinum group.

3..A conductive filament for igniters, incandescent lamps and the like,-composed of covering cores of .ducti1e 2. A conductive filamentfor igniters, i candescent lamps andthe like, composed of a refractory metallic core and a sheath cona core of tantalum and a sheath containing This specification signed and witnessed a metal of the platirlium group. this 29th day of September, 1910.

4. A conductlve ament for igniters composed of a core of tantalum and a sheath HOWARD LYON 5 cpnsisting 'of material having a catalytic Witnesses:

action upon illuminating gas, substantially JOSEPH H. JOHNSON, as set forth. OLA C. SELLERS. 

